NASA-led study: extreme geomagnetic storms may hit twice as hard as thought

A NASA-led team argues that a long-assumed ceiling on Earth's geomagnetic response to solar storms may be a statistical illusion, and that the surface impact of the most extreme events could be about twice as large as previously expected, according to a New Atlas summary of research published in Nature. Scientists have used polar magnetometer readings and solar-wind measurements from distant probes to estimate how strong geomagnetic storms can become. Over time, the relationship between storm strength and cross-polar measurements appeared curved, as if geomagnetic activity leveled off at a saturation point. Researchers had proposed physical explanations involving particle oscillations, field-line reconnection rates, or plasma pressure dynamics. Reexamining the data and correcting for measurement uncertainties, the team concluded that regression to the mean better explains the apparent curve. Uncertainties in the timing and magnitude of solar-wind samples can make extreme readings look like they hit a cap. After those uncertainties are accounted for, the Earth's response looks linear throughout, leaving more room for a truly powerful solar storm to drive larger effects on satellites and power grids. The write-up places the work against the Carrington Event of 1859, still treated as the strongest geomagnetic storm on record, and notes the practical stake for a modern infrastructure of circuits and wiring. Source material attributes the argument to NASA-led scientists and the journal Nature.